refactor ec2 api wrappers to cloud package
switching off nginx access log to save on io.

can be switched on manually for debugging.
use python logging framework
Merge pull request #142 from tanmaykm/tanmaykm

minor refactors
auto account activations

New user registrations will not require invite codes any more. Accounts will be auto activated as long as the rate is within set limits. Beyond that, new accounts will be put into an auto approval queue, which shall activate based on a set rate.
nicer loading screen
faster loopback volumes with preloaded files

common files are pre-loaded on loopback disks to make them faster to assign to new sessions.
pre-loading is done when disks are returned to the pool.
upgrade to julia v0.3.3 build
Merge pull request #144 from tanmaykm/tanmaykm

auto account activation, better startup experience, Julia v0.3.3
dockerfile updates
Merge pull request #145 from tanmaykm/tanmaykm

dockerfile updates
update julia packages on running instances

Updates to Julia packages and user home image are now delivered through S3
and will not require creating a new AWS image any more.

Images are built and provisioned on S3 from any build machine.

Latest configured image is pulled on startup of a new ec2 instance and periodically on all
running ec2 instances.
Merge pull request #146 from tanmaykm/tanmaykm

update julia packages on running instances
use install_id as cluster id. fix user count query.
Merge pull request #148 from tanmaykm/tanmaykm

use install_id as cluster id. fix user count query.
activate user if login reattempted at lean time
Merge pull request #149 from tanmaykm/tanmaykm

activate user if login reattempted at lean time